Borough of Princeton Weather Forecast

    • 60
    • 88

    Rain Showers

    • 51
    • 73

    Rain Showers Likely

    • 50
    • 74

    Mostly Sunny

    • 55
    • 74

    Slight Chance Rain Showers

    • 52
    • 72

    Mostly Cloudy

    • 54
    • 81

    Mostly Sunny

    • 49
    • 74

    Mostly Sunny

Today 6 Sep Mercer

Mostly cloudy with a chance of Showers and Thunderstorms. Some Thunderstorms may be severe. Locally heavy rainfall possible. Hot with Highs in the upper 80s. Temperature falling into the lower 80s late. Southwest Winds 10 to 15 Mph with Gusts up to 25 Mph. Chance of rain 50 percent.

Tonight 6 Sep Mercer

Showers this Evening, then Showers likely with a slight chance of Thunderstorms after midnight. Lows in the upper 50s. Northwest Winds 5 to 10 Mph, becoming north after midnight. Chance of rain 90 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Borough of Princeton Temperature Statistics

September Temperature

Trenton, Mercer County Airport (9.3 miles)

  • Lowest 3 September, 2025

    54 °F

  • Average September

    67.1 °F

  • Highest 4 September, 2025

    84 °F

Climate (2020–Present)

Trenton, Mercer County Airport (9.3 miles)

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  • Average Low 2020–2025

    46.2 °F

  • Average 2020–2025

    55.3 °F

  • Average High 2020–2025

    64.4 °F
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